Silver bullets that kill bacteria, not werewolves

Silver engages in a multi-pronged assault on bacteria.

The use of silver in medicine is as old as Western medicine itself. Hippocrates is known to have used it to treat ulcers and wounds, the Romans almost certainly knew of its healing properties, and its use continued through the middle ages and up to the present day. In the antibiotic age, interest in silver may have waned a little. But with urgent need to fight antibiotic-resistant bacteria, there has been a resurgence in its use.

The reason is that silver can kill bacteria selectively, and more importantly, bacteria have been unable to develop resistance against it. Despite silver’s long medical history, we do not know how it operates.

A paper published today in the journal Science Translational Medicine sheds some light on silver’s success against bacteria. The most important finding is that silver—unlike most antibiotics—works in more than one way. This is perhaps why bacteria may find it difficult to build resistance to the chemical.

Here is silver’s multi-pronged approach: first, silver sticks very strongly to sulfur, found in parts of proteins. These sulfur groups normally bond to each other, holding proteins together and keeping the protein folded up in its correct shape. But if silver interacts with sulfur, then the protein cannot fold correctly, and thus it cannot do its job. Next, silver interferes with how bacteria use iron. Iron is often held in place within proteins by binding to sulfur. Since silver also interacts with sulfur, it blocks the iron from doing so. Finally, silver causes bacteria to produce extremely toxic substances called reactive oxygen species. These go on to cause damage inside the cell, harming the DNA, proteins, and even the membrane that surround cells.

The net result of this silver onslaught is bacteria with severe damage to their basic biochemistry. In addition, the membranes and walls that surround the bacteria are leakier after the silver treatment. This allows conventional antibiotics inside the cells; in their weakened state, the cells are much more susceptible to them. Bacteria are broadly classified into two groups, called Gram-negative and Gram-positive. Gram-negatives have an extra cell membrane that protects the bacteria, which makes it much more difficult for some antibiotics to penetrate the cell (examples include gentamicin and vancomycin). It seems that silver negates this advantage and allows even weaker drugs to do their jobs.

James Collins of Boston University, who led the research, showed that with added silver, less antibiotic drug is needed to kill the bugs. A great result in itself, but it gets better. Silver also reverses antibiotic resistance of E. Coli bacteria, making them, once more, susceptible to tetracycline.

These experiments not only worked in a Petri dish. When silver was added to standard antibiotics such as gentamicin and vancomycin, Collins could treat E. Coli infections in the bladder and abdomens of mice. Normally, these drugs have little effect on E. coli infections because they are designed to attack Gram-positive bacteria.

Finally, Collins showed that the mice themselves remain unharmed by silver. If he is able to repeat this work in humans, he may actually have a “silver bullet” for antibiotic resistance.

Very interesting to finally find out the exact chemistry of why silver works so well as an antibacterial. Unfortunately overuse of antibacterial and antimicrobial including silver is causing problems in the area of sewage treatment.

The massive overuse of antibacterial agents is one of society's hidden issues that is going to cause major problems over the next quarter century.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals. This bit on silver is just amazing. I would like to keep updated on this research.

Couldn't long-term use of silver-laced antibiotics result in argyria? Or are the amounts so miniscule as to not matter?

Highly unlikely. Every case of argyria I've studied has required that individuals take either superdoses of colloidal silver or work in a factory situation involving silver compounds. In both cases, it takes years of macro exposure.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

Does it count as "brutish" when your favorite spectator sport is people killing each other, or being ripped apart by wild beasts?

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

Mental note: "Keep this straight and you will survive the Werewolf Apocalypse... Werewolves are made of Bacteria... Bacteria is killed by penicillin.... save at least 3 pills from each prescription for future Werewolf Apocalypse defense jar"

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

Does it count as "brutish" when your favorite spectator sport is people killing each other, or being ripped apart by wild beasts?

Call me cynical, but I think that if it wasn't against the law in most countries, modern world Saturday evening Sport event wouldn't be UFC but a deadly variant (if it wasn't against the law to transmit such a show, many Media corporations would put shop in some place like Somalia and broadcast such events).

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals. This bit on silver is just amazing. I would like to keep updated on this research.

Whenever I meet someone with misconceptions about the level of sophistication of the ancient Greeks and Romans, I take the opportunity to introduce them to the Antikythera mechanism. Never fails to blow minds.

I get why is silver toxic to bacterial cells, but could someone explain why it's not toxic (in the same quantities) to ours in layman's terms...

Antibiotics are just as toxic to us. Pump enough of it into your body and you're just as dead from a silver overdose.

Since there are several orders of magnitude more of my cells in me than the bacteria (even in the bloodstream) why do they die in preference to my own cells?

Obviously I'm missing something but this doesn't seem to explain it.

I get that bacteria must have some process/form/chemical constituent that causes the antibiotic to either preferentially attack it, or which is not present in human cells to be damaged. Is silver similar in that the things it tends to interfere with affect bacteria faster/in lower concentrations or is it just that our larger bodies let us take the damage but repair/replace it in a way that a single cellular organism just can't compete with?

I know folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals. This bit on silver is just amazing. I would like to keep updated on this research.

Wow, 2500 years old. The oldest person I know was about 500 and he died about 20 years ago.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

Does it count as "brutish" when your favorite spectator sport is people killing each other, or being ripped apart by wild beasts?

Considering that was only done during the last throes of the Roman Empire, I'd say it's indicative of a failing way of life. I'm much more enamored with the fact they held live naval battle reenactments in the Coliseum than anything else.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

Does it count as "brutish" when your favorite spectator sport is people killing each other, or being ripped apart by wild beasts?

Considering that was only done during the last throes of the Roman Empire, I'd say it's indicative of a failing way of life. I'm much more enamored with the fact they held live naval battle reenactments in the Coliseum than anything else.

This is simply not true. Gladiator fights became popular during the Roman Republic.

I know that folks who lived 2500 years ago or there about didn't have internal combustion engines and microprocessors, but I get a little incensed when people portray any civilization that existed prior to the Renaissance as brutish neanderthals.

I don't know anyone who would realistically consider the Romans as brutish neanderthals.

Does it count as "brutish" when your favorite spectator sport is people killing each other, or being ripped apart by wild beasts?

Call me brutish and neanderthal but I think I'd like that spectator sport. I'd definitely won't be any good at it.

In the future we will be providing bacterial injections to solve and "cure" these problems. We keep screwing with things we really don't know a lot about. What we know about bacteria and how it works in our body pales in comparison to what we don't know. People keep dying from c-diff and babies are dying from nec every day because we have screwed with the microbiome in our bodies willy nilly for so long we might not even be able to figure out what and how much should be there. The relationship between us and the bacteria that live within us is very symbiotic and we keep trying to kill them instead of keeping them balanced which would lead to much better health. Being as it is all about money and not really getting people healthy it won't change. Healthy people don't need the drug companies but sick people do!! Stop it people stop giving your money to them so they can keep this ridiculous circle going.

I think you are messing our symbiotic bacterias with the ones that cause us harm.

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